All adult (> 18 years old) patients with diagnosis community-acquired pneumonia will receive initial antibiotic therapy based on local guidelines and susceptibility patterns, according to the decision of the treating physician.Patients will be randomly assigned to one of two groups, which respectively include PCR and PCT clinical procedure protocol. Randomization will be done using a table of random numbers generated by computer. For practical reasons the doctors treating the patients in question have science group in which the patient was included.